Under-pressure plugging structure for high-water-pressure confined water precipitation well

The utility model provides a high-water-pressure confined water dewatering well under-pressure plugging structure which comprises a dewatering well casing, the dewatering well casing is arranged in a stratum, and a cushion layer and a bottom plate are sequentially arranged above the stratum from bottom to top. A first drainage pipe is arranged in the dewatering well casing, and the upper end of the first drainage pipe is connected with a second drainage pipe; the second drainage pipe extends out of the upper end of the dewatering well inlet pipe and is connected with a water suction pump, and a valve is further arranged at the upper end of the first drainage pipe. The dewatering well casing is sequentially provided with a sandy gravel layer, a quick-setting cement layer and a concrete layer from bottom to top, and the upper end of the first drainage pipe is embedded in the concrete layer; and when the quick-setting cement layer is laid, the valve is closed, the second drainage pipe is detached, and then the c